An eleventh-hour action plan is on the table to save iconic kauri in Northland's Waipoua Forest after intensive discussions between iwi, DOC and scientists.

Photo: RNZ / Claire Eastham-Farrelly

DOC confirmed last month that the fungal disease phytopthera agathidicida had infected a tree just 60 metres away from Tāne Mahuta, although the forest giant itself still appears healthy.

The discovery of kauri die-back so close to the most famous tree in New Zealand may have galvanised officialdom into a protection plan for Waipoua, but it has also had an unexpected effect: a sudden rise in visitors to the big trees.

Visitor numbers usually drop off in winter, according to the kaitiaki, Te Roroa.

But since news broke of the risk to Tāne Mahuta the iwi has had to reinstate its summer guides, known as forest ambassadors, to make sure people do not leave the tracks and spread the disease.

Te Roroa's science advisor Taohau Patuawa said people were assuming that DOC and the iwi would immediately close the Waipoua tracks.

"People were coming up to have one last look at Tāne Mahuta," he said.

The ambassadors were forced to head off one lot who jumped off the boardwalk determined to give Tāne a farewell group hug, Mr Patuawa said.

"I think once they were told about the risk they were remorseful, but that's not good enough," he said.

Lincoln scientist Amanda Black, who raised the alarm last month about the risk to Tāne Mahuta, would prefer to see the Waipoua tracks closed, to give the forest a rest from its 200,000 visitors a year.

However Te Roroa were reluctant to do that, and it was their call, Dr Black said.

"I don't think that's something we can overstep. We are not the forest owners; they are the mana whenua."

In Auckland's Waitakere forests, the council has closed tracks at the request of iwi, until they can be made safe.

But Te Roroa and DOC believe Waipoua kauri are already the best protected in New Zealand, with high-grade tracks, boardwalks and shoe hygiene stations.

They have now agreed on a plan of action to boost that protection even further.

DOC's Kaipara manager, Stephen Soole, said the ambassadors' contracts would be extended to cover the whole year and physical barriers will be installed along the boardwalks.

"We've agreed to increase the signage, and we will start a five-year feral pig control programme later this year," he said.

The plan also suggests the infected tree near Tāne Mahuta could be treated with phosphite.

Te Roroa have yet to approve that.

But trials conducted by Plant and Food Research have shown that kauri injected with the chemical have managed to fight off the disease, and the bleeding lesions on their trunks have healed.

The scientist in charge, Dr Ian Horner, said it would make sense to treat the infected tree.

"It might help to stop the spread of the disease in the vicinity of Tāne Mahuta and it certainly might reduce the impact that tree will have in terms of producing more spores so it's probably a good idea," he said.

Dr Horner said he was impressed with Te Roroa's protection plan for Waipoua, which also includes the soil-sampling scientists have been advocating, to find out how close the pathogen has crept to Tāne Mahuta.

New high-tech aerial surveys to track the disease will also begin this spring.

All of those measures should have happened years ago, and it wasn't for lack of asking, according to Taohau Patuawa.

In his view the Kauri Dieback Programme led by the Ministry for Primary Industries had failed to deliver for Waipoua.

"That really was set up to be the flagship that made good decisions about how we managed the risk, the spread (of kauri dieback) and quite possibly wasn't up to the task. Certainly it didn't perform, historically," he said.

Mr Patuawa, who is now on the Kauri Dieback governance group himself, said he believed the programme was now heading in the right direction, and he hoped it was not too late to save the big trees.